1) Stir the cup of soil and water again. What happens to the soil when the water begins to move?
All the humus went down in some of the water to the bottom.


2) What happens to the soil when the water slows down?
It all goes down to the bottom really slowly.

3) Which soil component drops to the bottom of the cup first?
The gravel.


Why do you think that happens?
It went down first because it was the heaviest.


4) Which soil floats on the water?
The humus.


Why do you think this happens? It floated because it was the lightest.

Vocabulary

Gravel tiny rocks

Sand: little partickles of crystals